Lifting jack



Oct. 23, 1928.

C. D. ELLWOOD LIFTING JACK.

Filed April 26, 1926 5 sheets-sheet 1 TufeTL 0T* m, MN QN N E N C. D.ELLWOOD LIFTING JACK Filed April 26, 1926 5 Sheets-Sheet wm @www C. D.ELLWOOD ci 23, W28.

LIFTING JACK Filed April 26, 1926 3 Sheets-Sheet mm@ UMH/w Elli PatentedOct. 23, 1928.

UNITED STATES PATENT `o1=l=1cl:r..-

CHARLES D. EIJLWOOI), OF RACINE, WISCONSIN, ASSIGNOR TO WALKER MANUFAC-TUBING COMPANY, 0F RACINE, WISCONSIN, A CORPORATION OF WISCONSIN.

LIFTIN G 'JACKv Application led April 26, 1926c ASerial No. 104,760.

This invention relates to lifting jacks, and

more particularly to a4 heavy duty 4jack designed for use about garagesand repair shops lmechanism carried by the carriage is of very smallheight, or is capable of being depressed to an extremely low position,so that the assembly can be pushed under very low hanging loads, andoperated in this position. The

lifting mechanism mounted at the forward' end y:of the carriagecomprises a bell crank lever having a rather long forwardly extendinglifting arm, and a comparatively short downwardly extending power arm.'lhe driving and reversing mechanism is located at the rear of t-hejack, and a horizontally movable rackbar or push-rod acts against vthedownwardly extending power arm of the bell crank. The driving mechanismis actuated b a long, jointed actuating handle or lever. he main portionof this lever always extends substantially .horizontally from thecarriage, and when operated, swings vertically through. a compartivelyshort arc.. rllhis portion of the handle is, like the carriage, adaptedto be operated beneath the low hanging portions of a truck or bus. Anextension member is pivoted to the rear endof this main handle portion,the extension being operable in either a horizontal or verticalposition, or if desired, in an intermediate position, according to thespace `available for such operatiorm L @ne object of the invention is toprovide a jack of the type described, which is extremely low, so as tooperate beneath very low hanging loads, and at the same time one whichmay be easily shifted into position and which may be convenientlyoperated from a distance.

Another object is to provide a new and im- Another object is to providean improved form of operating lever or handle, which is capable ofadjustment to the most convenient position for operating under very lowhanging loads.

Other objects and advantages of this invention will be apparent from thefollowing detailed description of certain approved forms of theapparatus.V Y

ln the accompanying drawings:

lig. les a side elevation of the complete Jac Fig. 2 is a plan View,partially broken away, of the carriage, this View being on aconsiderably larger scale than Fig. l.

Fig. y3 is a longitudinal vertical section through the portions of thejack shown in Fig. 2.

Fig. 4 is a transverse vertical section taken substantially on the line4 4 of Fig. 3.

Fig. 5 is a detail of the operating handle, on an enlarged scale.

Fig. tl is a detail view showing the adjustlng handle for the operatinglever. 'l

Fig. 7 is a view, similar to Fig. 3, showing a modification of thelifting mechanism.

The main supporting frame l carries at its front end an axle 2, on theends of which are mounted the supporting rollers 3. Near the rear end ofthe frame, a pair of rollers 4 are swiveled on vert-ical axes 5 in theoutwardly projecting bracket arms 6, rlhe swiveled rollers 4 permit thecarriage to be steered into position under any desired portion of theload, and enable the carriage to be turned on a short radius. The frontrollers `3 have a rather wide wheel base, and the brackets 6 space therollers 4 even farther apart so that a wideirm foundation is providedfor the jack,

The lifting provide two side arms l0, which are pivoted at 1l, to thesides of one upper corner of the lifting Sleeve l2. A link or reach rod13 is forked at its lower forward end and pivoted at i4 about a lug l5extending from the lower dei roe

corner of lifting sleeve 12, and its upper rear end is pivoted on ashaft 16 extending between the side members of frame 1. The spacing ofshafts 9 and 16 is substantially the same as the spacing of shafts 11and 14,

vand the reach rod 13 is of substantially the same effective length asthe load arm 7 of the bell crank, so'that the plane of the axesl ofshafts 11 and 14 will always remain substantially arallel to the planeof the axes of shaftsg and 16. A lifting head or shoe 17 having aplurality of upwardly extending lugs 18 to support the load is carriedby a vertical stud or shaft 19'threaded to engage in a nut 20 mountedwithin the lifting sleeve 12. The downwardly extending powerv arm 8 ofthe bell crank consists of a pair of similar side members spaced apartto permit the link or reach rod 13 to pass therebetween. Upon a shaft 21mounted in the lower ends ofthe power arms 8 is mounted a broad facedantifriction roller 22.

As power is applied to the lower end of the downwardly extending powerarm 8, in the form of a p'ush from right to left, as seen in Fig. 3, theload arm 7 will be elevated, different elevated positions beingindicated in dotted lines in Fig. 3. It will be noted that the parallelarm movements of link 13 and arm 7 will cause the sleeve 12 to move sothat the axis of screw shaft 19 will remain vertical at all times, andhence the lifting head or sleeve 17 will always remain horizontal inproper load-supporting position. When the shaft 19 is screwed downwithin sleeve 12 as far as possibleand the load arm 7 is comletelylowered, as indicated in solid lines in ig. 3, the lifting head or shoe17 will be positioned only slightly above the upper faces of sup ortingrollers 3 and may be positioned' beneat a very low hanging load. If ahigher -load is to be engaged, and a greater vertical lift is desired,the shoe 17 may be rotated by hand to elevate the screw 19, thusincreasing the initial elevation of the shoe and conse# quentlyincreasing the height to which it will be elevated when the lifting bellcrank is operated.

In the form of bell crank shown in Fig. 3, the remote ends of the forkedextensions of load arm 7 and power arm 8 are bridged by side connectingmembers 23, which span the sides of reach rod or link' 13 and serve tostrengthen the bell crank.

Any approved means may be used for aplying power to swing the wer arm 8of the hell crank, one improved orm of such mechanism being indicated inFigs. 2 and 3. push-rod or rack bar 24, provided with teeth 24 on itsupper surface, is guided for hori` zontal sliding movement in theframe 1. A cross-head`25 is mounted on the front end of this rack bar24, and a horizontal shaft 26 passing through the rack bar andcross-head carries guide rollers 27 on its ends` the .rollers beingconfined between horizontal trackways 28 in the frame 1. The cross-headhas 'a broad, flat face 29, positioned in a vertical plane, againstwhich the roller 22 on power arm 8, is adapted to engage. It will benoted that .the lower end o f power arm 8 swings through a rather longflat arc in a vertical plane, whereas the rack bar 24 has a Arectilinearmovement in this sameplane. During this movement the roller 22 will moveup and down along the fiat forward face 29 of the cross-head.l

A driving pinion 30 mounted on a horizontal shaft 31 is always in meshwith the rack bar 24.- A ratchet wheel 32 is also secured to shaft 31at'one side of the pinion 30. The main actuatin handle or lever 33 has ahousing 34 secure to its forward end, the housing being pivoted at 35 ona horizontal shaft in the upper rear portion of supporting frame 1. Anactuating pawl 36 is pivoted on shaft 37 within housing 34, and normallyheld by spring 38 in-engageinent with the teeth of ratchet wheel 32. Alocking pawl 39 is pivoted on horizontal shaft 40 in the frame 1, and isnormally held by spring 41 in engagement with the teeth of ratchet wheel32. i 1

The adjustable extension 42 of the operating handle is pivoted at 43 tothe rear end 'of the main operating lever 33. An arcuate plate 44mounted on the rear end of lever 33 extends between the forked lower endportions of extension 42, and is provided with a series'of notches 45 tobe selectively engaged 10 handle or loop 48 by means of which the dog105 may be retracted against the action of spring 49 and moved toanother selected notch 45 in the arcuate plate 44. In this way, theexten'- sion 42 can be used as a substantially horizontal extension ofthe main lever 33, as 'shown in 110 Fig. 1, or may be moved to avertical position, as indicated in dotted lines in said figure. Byproviding sufficient intermediate notches 45, the extension 42 may bemoved to any desired position intermediate the two positions.

indicated.

When the jack is being operated, the main handle portion 33 isoscillated up `and down through a comparatively shortarc so that italways extends substantially in a horizontal direction and may beoperated beneath very low hanging parts of a carriage frame, such A asthe rear end of a bus. The handle portion 33 is of such length that therear end thereof will ordinarily project out from beneath the load, andthe extension member 42 may be inclined at a convenient angle foroperation. -If there is not sufficient room to have this extension42`project horizontally or at an angle, it may be arranged vertically,as shown 13 in dotted lines, Fig. 1, and the jack operated by impartingan up and down motion to this extension 42. If over-head members preventthe upward inclination of handle 42, it`

may be used as substantially a horizontal extension of the main handle33, as indicated in solid lines, Fig. 1.

:When the jack is to be used to elevate a load, the carriage 1 is shovedinto position beneath the load, by means of the handle 42, the swiveledrear wheels or rollers 4 permitting the carriage to be steered into thedesired position. When lifting head 17 is beneath Athe load, the`lever33 is oscillated up'and tooth is being held in position by the lockingpawl 39 which is in engagement with another tooth of the ratchet. On thedownstroke of lever 33, the pawl 36 will rotate the ratchet 32 in aclockwise direction, as seen in Fig. 3, the length of one ratchet tooth,until the locking pawl 39 has snapped into engagement with the nextsucceeding tooth. Repeated oscillations of the lever 33 will graduallyrotate the ratchet 32, and consequently-the pinion 30, in a clockwisedirection, and slowly impart-a rectilinear sliding movement toward theleft, as seen in Fig. 3, to the rack bar 24. Since cross-head 25 ispressing against the roller 22 at the lower end of power arm 8 of thebell crank, the bell crank will be swung about its pivot 9 to graduallyelevate the load arm 7 to the dotted positions indicated in F ig. 3. Aspreviously noted, the reach rod 13 operates to maintain the lifting head17 in a horizontal position beneath 'the load at all elevations of theload arm 7.

vWhen tlfe load is to be lowered, it is necessary to gradually retractthe rack bar 24,

toward the right in Fig. 3, and this is done by permitting a gradualcounter-clockwise rotation of the ratchet 32. Numerous forms ofreversing mechanisms are well known in this art for controllingthelifting and locking pawls to permit the reverse movement of theratchet as the-operating lever is oscillatecl. The mechanism hereartially indicated is of the type disclosed andD claimed in thecopending application of Dearsley Serial No. 73,187, led December 4,1925. Briefly described, a reversing member 50, pivoted about the axisof shaft 31, is normally actuated in one direction by a spning 51confined between a lug 52 on supporting frame 1 and a bracket extension53 on the reversing member 50. When permitted to move under theinfluence of spring 51, the reversin member will, through camprojections whic successively engage the two pawls, alternately pushthese pawls,y

out of engagement with thev ratchet wheel 32. The operation is such thatthe lifting pawl 36 will be engaged with the ratchet and the lockingpawl 39 will be held out of engagement during the upstroke of the lever33, so as to permit a partial counter clockwise rotation of the ratchet.During-the down-stroke Iof the lever 33, the locking pawl will hold theratchet, but the operatln pawl 36 will be disengaged. 'lhus the v oad isgradually lowered.' During the lifting operation, reversing member 50 isheld out of operation, with spring 51 compressed, by means of a linkconnection extending to the operating lever 54 carried by the lever 33.Since the specific form of this reversing mechanism forms no part of thepresent invention, further description thereof should be unnecessary.Other forms of reversing and liftin l mechanism could be substituted,although t e form here indicated is preferred.

A somewhat modified form of the lifting mechanism at the front end ofthe jack is shown in Fig. 7. As here shown, the lifting .bell crankcomprises a forwardly extending load arm 55, and a downwardly extendingpower arm 56, the bell crank being pivoted intermediately on horizontalshaft '57 in the supporting frame 1. The forwardly extending load arm 55is formed of two similar side members, or is forked, and the free endspivoted on shaft 58 at the upper end of lifting sleeve 59. A pair ofsimilar links or reach rods 60 have their forward ends pivoted at 61 tothe lower end of the lifting sleeve .59," and their rear ends arepivoted at 62 to the respective sides of supporting frame 1. Thedownwardly extending power arm Y 56 is pivoted at its lower end at 63 tothe forward end of an operating rod 64, which may be connected at itsother end to a rack bar similar to the rack bar 24 hereinabovedescribed, or may be connected with any other suitable form of operatingmechanism. Lifting head or shoe 17 has its vertically extending screwshaft 19 threaded into a nut 420 carried by sleeve 59, whereby thelifting shoe Can be verticall adjusted within the sleeve, all as'describe hereinabove, in connection with the first described form ofjack.' The spacing of the axes of pivots 57 and 58 is the same as thatbetween pivots 61 and 62, also pivots 57 and 62 are spaced the same aspivots 58 and 61, so that the reach rods 60 will serve to give aparallel motion to the sleeve 59 and always maintain the lifting head orshoe 17 in a horizontal position. Different portions of the severalparts, when the jack is elevated,

pivoted at the free end of the forwardly extending arm, means formaintaining the lifting head horizontal at all elevations, a pushrodguided for horizontal movement in the frame, power means forreciprocating the rod, a cross-head at the forward end of the rod, andmeans at the free end of the power arm of the bell-crank which swings ina vertical arc across the path of the push-rod and is engaged by thecross-head.

2. In a lifting jack, a supporting frame, a bell crank lever pivoted inthe frame to oscillate in a vertical plane and comprising a forwardlyextending lifting arm and a downwardly extending power arm, a liftinghead pivoted at the free end of the forwardly extending arm, aI push-rodguided for horizontal movement in the frame, means for reciprocating therod, a cross-hea l at the forward end of the rod, and means at the freeend of the power arm of the bell-crank which swings in a vertical arcacross the path pf the pushrod and is engaged by the cross-head.

3. In a lifting jack, a supporting frame, a bell crank lever pivoted inthe frame and comprising a. forwardly extending lifting arm and adownwardly extending power arm,

a lifting head pivoted at the free end of the forwardly extending arm, apush-rod guided for horizontal movement in the frame, a cross-headcarried by the forward end of the push-rod, a roller pivoted at eachside of the cross-head, track-ways in the frame for the rollers, aroller pivoted in the lower free end of the power arm of the bell crankand adapted to engage against the front face of the cross-head, andmeans for reciprocating the push-rod in the frame.

4. In a lifting jack, a supporting frame, a bell crank lever pivoted inthe frame and comprising a forwardly extending lifting arm and adownwardl extending power arm, a lifting head pivote at the free end ofthe forwardly extending arm, a rack-bar guided for horizontal movementin the frame, a cross-head mounted at the forward end of the rack bar,rollers pivoted at the sides of the crosshead, track-ways in the framefor the rollers, a roller pivoted at the free lower end of the power armof the bell crank and ada ted to engage against the front face of t ecross-head, a pinion mounted in the frame and engaging the rack, andmeans for rotating the pinion in either direction.

5. In a lifting jack, a supporting frame, lifting kmeans pivoted in theframe to oscillatein a vertical plane and comprising a lever arm,aroller pivoted in the free end of the arm and adapted to swing in avertical arc, a member guided for rectilinear movement in the frame inthe plane of movement of the lever and having a substantiall flat faceextending at right angles to its ine of move ment against which theroller engages, means for guiding the member, and means forreciprocating t-he member in the frame.

6. A lifting jack comprising a carriage, rollers for supporting thecarriage, lifting means mounted in the forward ortion of the carriage,means for raising an lowerin the lifting means comprising an operatinglever pivoted to the rear of the carnage, the lever comprisingr a mainportion which extends substantially horizontally and is adapted to swingthrough a short vertical are, and an extension pivotally attached to thefree end of the main lever and adjustable to extend upwardly therefromat any selected one of a plurality of angles, and means for rigidlyholding the lever sections together in any selected position ofadjustment.

CHARLES D. ELLWOOD. l

